JP7198701B2 - Fiber-reinforced plastic composites, fiber-reinforced plastic preforms, and fiber-reinforced plastic intermediate substrates - Google Patents

Description

The present invention relates to fiber-reinforced plastic composites, fiber-reinforced plastic preforms, and fiber-reinforced plastic intermediate substrates. Hereinafter, the fiber-reinforced plastic composite material is referred to as "FRP composite material," the fiber-reinforced plastic preform as "FRP preform," and the fiber-reinforced plastic intermediate substrate as "FRP substrate."

Patent Document 1 discloses a bent fiber-reinforced prepreg sheet in which reinforcing fibers are aligned in one direction and aligned on a plane, and in which the reinforcing fibers are periodically bent in the plane and impregnated and fixed with a resin. .

WO2016/208450

The bent fiber-reinforced prepreg sheet can be stretched in-plane during molding by stretching such that the bent reinforcing fibers are unfolded. Therefore, even when molded into a three-dimensional curved shape, excellent appearance quality can be obtained. On the other hand, since the reinforcing fibers are in a bent state even after molding, it is difficult to obtain a high-strength molded product from the bent fiber-reinforced prepreg sheet.

An object of the present invention is to provide an FRP composite material, an FRP preform, and an FRP base material that are capable of obtaining excellent strength and appearance quality.

One aspect of the present invention is a plate-like FRP composite material having a curved portion curved in the thickness direction. The curved portion includes one or more first layers in which the reinforcing fibers are aligned in a straight line, and one layer in which the reinforcing fibers are aligned and meandering with an amplitude in a direction perpendicular to the thickness direction. and the second layer described above. At least one of the outermost layer and the innermost layer of the curved portion is composed of the second layer.

Another aspect of the present invention is a plate-like FRP preform having a curved portion curved in the thickness direction. The curved portion includes one or more first layers in which the reinforcing fibers are aligned in a straight line, and one layer in which the reinforcing fibers are aligned and meandering with an amplitude in a direction perpendicular to the thickness direction. and the second layer described above. At least one of the outermost layer and the innermost layer of the curved portion is composed of the second layer.

Yet another aspect of the present invention is an FRP substrate in which a plurality of layers are laminated in the lamination direction. The plurality of layers includes one or more first layers in which the reinforcing fibers are arranged in a straight line, and one or more second layers in which the reinforcing fibers meander with amplitude in a direction perpendicular to the lamination direction. and consists of At least one of the outermost layers in the stacking direction is composed of the second layer.

According to the present invention, it is possible to provide an FRP composite material, an FRP preform, and an FRP base material that are capable of obtaining excellent strength and appearance quality.

1 is a cross-sectional view of an FRP substrate; FIG. 1 is a partial cross-sectional plan view of an FRP base material; FIG. FIG. 4A is a cross-sectional view of a curved portion of an FRP base material, an FRP composite material, and an FRP preform; It is the figure which looked at the outer peripheral surface of the curved part of FIG. 3 from the curvature radial direction outer side. It is the figure which looked at the internal peripheral surface of the curved part of FIG. 3 from the curvature radial direction inner side.

An FRP base material 1, an FRP composite material 2, and an FRP preform 3 according to embodiments will be described with reference to FIGS. 1 to 5. FIG. In the following description, elements having the same functions are denoted by the same reference numerals, and overlapping descriptions are omitted.

<FRP base material>
The FRP base material 1 is an intermediate base material that is formed into an FRP composite material 2 as a molded product or an FRP preform 3 as a preformed product by press molding or the like. The FRP composite material 2 and the FRP preform 3 will be described later.

The FRP base material 1 is a laminate S formed by laminating a plurality of prepreg sheets p in the lamination direction Z, as shown in FIGS. Each prepreg sheet p is composed of reinforcing fibers F, which are continuous fibers aligned in a direction orthogonal to the lamination direction Z, and semi-cured resin R impregnated in the reinforcing fibers F. Hereinafter, the direction orthogonal to the stacking direction Z, that is, the direction orthogonal to the thickness direction, or the direction parallel to the XY plane is also referred to as the "plane direction".

The material of the reinforcing fiber F is not particularly limited, and carbon fiber, glass fiber, polyaramid fiber, alumina fiber, silicon carbide fiber, boron fiber, silicon carbide fiber, etc. can be used, for example. Carbon fibers that can be used include, for example, polyacrylonitrile (PAN-based), pitch-based, cellulose-based, vapor-grown carbon fibers using hydrocarbons, graphite fibers, and the like. Two or more of these fibers may be used in combination.

The material of the resin R, which is the matrix material, is not particularly limited. A thermosetting resin or a thermoplastic resin can be used.

The laminate S includes two types of layers having different forms of reinforcing fibers F, specifically, a first layer L1 (hereinafter referred to as "layer L1") and a second layer L2 (hereinafter referred to as "layer L2”). In the laminate S, both of the outermost two outermost layers Ls in the lamination direction Z are composed of the layer L2. A layer Lsa adjacent to the outermost layer Ls on the inner side in the stacking direction Z is composed of the layer L1. The number and lamination order of the layers L1 and L2 in the layers other than the outermost layer Ls and the layer Lsa adjacent thereto are not particularly limited, and can be appropriately set according to the strength, rigidity, etc. required for the molded product. In the laminate S according to this embodiment, all core layers other than the outermost layer Ls are composed of the layer L1.

The layer L1 is a layer in which reinforcing fibers F are aligned in one direction and extend linearly and substantially parallel to each other. In the core layer of the laminate S other than the outermost layer Ls, a plurality of layers L1 are laminated with different angles to each other. For example, as shown in FIG. 2, the plurality of layers L1 can be laminated such that the fiber orientation angles are 90°/−45°/45° . . . from one side in the lamination direction Z. Note that the combination of fiber orientation angles and the order of lamination are not limited to this. For example, the fiber orientation angle of each layer L1 is set so that the molded product can obtain isotropic strength characteristics by combining all the layers L1 and a layer L2 in which the reinforcing fibers F are stretched, which will be described later. may be selected.

The layer L2 is a layer in which the reinforcing fibers F meander with geometrical periodicity in the surface direction. In the layer L2, the aligned reinforcing fibers F meander and extend with an amplitude A in the plane direction while maintaining a state of being substantially parallel to each other. Assuming that the extending direction of the meandering reinforcing fibers F, that is, the direction of 0°, is the X direction, and the direction perpendicular to it, that is, the direction of 90°, is the Y direction, the meandering waveform of the reinforcing fibers F is as follows: They are arranged at a constant pitch P in the X direction and have an amplitude A in the Y direction. Although the pitch P and the amplitude A are not particularly limited, for example, the pitch P is 10 to 50 mm and the amplitude A is 2 to 30 mm. The waveform of this embodiment is triangular, and has tops Fp that define the amplitude A and side portions Fs that connect the tops Fp. The waveform may be a sine wave, a rectangular wave, a sawtooth wave, or the like, in addition to the triangular wave. The meandering reinforcing fibers F can be formed by a known method such as the method described in Patent Document 1 above.

The effects of this embodiment will be described below.

(1) According to the FRP base material 1, as shown in FIG. 2, the reinforcing fibers F of the outermost layer Ls meander with an amplitude A in the plane direction. Therefore, when a tensile load in the X direction acts on the reinforcing fibers F of the outermost layer Ls during molding, the waveform of the reinforcing fibers F is deformed so as to expand the pitch P and reduce the amplitude A (Fig. 4 reference). As a result, the reinforcing fibers F of the outermost layer Ls can seemingly extend uniformly along the X direction without causing insufficient fiber length. Further, when a compressive load in the X direction acts on the reinforcing fibers F of the outermost layer Ls during molding, the waveform of the reinforcing fibers F is deformed so that the pitch P is reduced and the amplitude A is increased (Fig. 5). As a result, the reinforcing fibers F of the outermost layer Ls can seemingly contract uniformly along the X direction without causing local fiber buckling.

For example, when the FRP base material 1 is curved and deformed in the thickness direction to form the curved portion B (see FIG. 3), the outermost layer Lo located on the outermost side in the curvature radius direction r of the curved portion B A tensile stress is generated, and a compressive stress is generated in the innermost layer Li located on the innermost side in the same direction r. Even in such a case, according to the FRP base material 1, the reinforcing fibers F of the outermost layer Ls, which is the outermost layer Lo, can be uniformly elongated as shown in FIG. The reinforcing fibers F of the surface layer Ls can be uniformly shrunk as shown in FIG. As a result, it is possible to suppress buckling due to excess fibers in the innermost layer Li and pulling of fibers inward in the curvature radius direction r due to insufficient fiber length in the outermost layer Lo, thereby improving the appearance quality of the molded product. can.

In addition, in the FRP base material 1, since the layer L1 having the reinforcing fibers F arranged in a straight line constitutes the core layer, the molded product is more likely to be produced than when the core layer is constituted by the meandering reinforcing fibers F. Strength can be increased. That is, according to the FRP base material 1, it is possible to achieve both high strength and improved appearance quality of the molded product.

(2) In the FRP base material 1, the outermost layer Ls is composed of the layer L2, and the layer Lsa adjacent thereto in the stacking direction Z is composed of the layer L1. Therefore, the meandering reinforcing fibers F (hereinafter also referred to as “wavy fibers”) and the linearly aligned reinforcing fibers F (hereinafter also referred to as “linear fibers”) in the outermost layer Ls are stacked in the direction of lamination. Adjacent and tangent to Z.

Therefore, during molding, when the corrugated fibers deform the corrugations and move relative to the straight fibers in the softened resin R, the corrugated fibers move in the out-of-plane direction (the stacking direction Z) due to the straight fibers. are guided so as to move relative to each other while being restricted from moving relative to each other. Specifically, at the interface between the layers L1 and L2, the linear fibers arranged in parallel on the layer L1 side and the wavy fibers arranged in parallel on the layer L2 side come into contact with each other. The surface formed by the parallel straight fibers is smoother than the surface formed by the parallel wavy fibers due to the absence of meandering of the fibers, and the relative movement of the abutting wavy fibers is less likely to be hindered. Therefore, the corrugated fibers contacting the surface formed by the parallel straight fibers are more likely to contact the surface formed by the corrugated fibers during molding than the corrugated fibers contacting the surface formed by the parallel corrugated fibers. It is easy to slide without causing catching, and the fiber arrangement is less likely to be disturbed.

In particular, when the outermost layer Ls is the innermost layer Li of the curved portion B, a compressive force acts on the corrugated fibers in the extending direction (X direction) during molding. The movement direction of the fiber tends to be unstable when moving inside. For example, the top Fp tries to move in the Y direction while being pushed by two sides Fs connected to the top Fp, but the top Fp pushed by the two sides Fs is in an unstable equilibrium state. Therefore, the moving direction tends to deviate in the out-of-plane direction. Even in such a case, according to the FRP base material 1, the linear fibers of the layer Lsa adjacent to the outermost layer Ls control the moving direction of the wavy fibers of the outermost layer Ls. Specifically, the straight fibers of the adjacent layer Lsa can prevent the reinforcing fibers F of the outermost layer Ls from penetrating into the adjacent layer Lsa. This further improves the appearance quality of the molded product.

(3) Furthermore, in the FRP base material 1, the extending direction (X direction) of the corrugated fibers of the layer L2, which is the outermost layer Ls, and the extending direction of the straight fibers of the layer L1, which is the layer Lsa adjacent to the outermost layer Ls, It is perpendicular to the present direction (Y direction). That is, the direction in which the apex Fp moves when the corrugated fibers of the outermost layer Ls are deformed by receiving a compressive load in the extending direction during molding coincides with the extending direction of the linear fibers. Therefore, the top portion Fp is smoothly guided by the linear fibers of the adjacent layer Lsa, and can move in the Y direction with good stability. This further improves the appearance quality of the molded product.

<Modification>
In the FRP base material 1 according to this embodiment, both of the two outermost layers Ls are composed of the layer L2, but at least one of the outermost layers Ls may be composed of the layer L2. Also in this case, the effect (1) can be obtained in the outermost layer Ls composed of the layer L2.

Also, in the FRP base material 1, a plurality of layers L1 are laminated, but the number of layers L1 may be one or more. Furthermore, in the FRP base material 1, the outermost layer Ls is composed of one layer L2, but the outermost layer Ls may be composed of a plurality of layers L2. In any of these cases, the layer L2 forming the outermost layer Ls and the layer L1 forming the layer Lsa are adjacent to each other in the stacking direction Z, so that the above effect (2) can be obtained. Further, in the FRP base material 1, the core layer other than the outermost layer Ls is composed of a plurality of layers L1, but a layer L2 may be interposed between the plurality of layers L1. The same effect as the above (2) can be obtained between the intervening layer L2 and the adjacent layer L1.

When the outermost layer Ls of the FRP base material 1 is composed of a plurality of layers L2, for example, in order to obtain isotropic strength characteristics in the outermost layer Ls, the extending direction of the corrugated fibers of each layer L2 is aligned with the stacking direction Z The layers may be laminated in order from the outside so as to form 90°/−45°/45°/0°. In this case as well, at the interface between the outermost layer Ls and the layer Lsa, the extending direction of the wavy fibers (X direction) and the extending direction of the straight fibers (Y direction) are perpendicular to each other. The effect of (3) can be obtained.

<FRP composite material>
Next, an FRP composite material 2 according to another embodiment will be described. As shown in FIG. 3, the FRP composite material 2 is a plate-like member having a curved portion B curved in the thickness direction at least partially. In addition, the shape of the curved portion B is not limited to the one shown in the figure, and may be one in which the radius of curvature changes depending on the position, or may be a three-dimensional curved surface shape. Further, the shape of the portion of the FRP composite material 2 other than the curved portion B is not particularly limited, and may be flat.

The FRP composite material 2 is a molded article obtained from the FRP base material 1 described above. Therefore, the curved portion B is composed of two layers L2 and a plurality of layers L1 laminated therebetween. In the layer L1, the reinforcing fibers F are arranged linearly along the surface direction. The planar direction of the curved portion B is a direction orthogonal to the thickness direction of the curved portion B, that is, a direction orthogonal to the stacking direction Z of the layers L1 and L2, or a direction orthogonal to the curvature radius direction r. The linear shape along the surface direction means that the FRP base material 1 is linear when it is returned to a flat state before being curved, or when the curved portion B is virtually expanded on a plane. means.

In the layer L2, the reinforcing fibers F are aligned and meander with an amplitude A in the plane direction. In the present embodiment, the extending direction (X direction) of the reinforcing fibers F of the layer L2 coincides with the direction of the maximum curvature line of the surface of the curved portion B (θ direction). Note that the reinforcing fibers F of the layer L2 only need to extend across the curved portion B when viewed in the thickness direction of the curved portion B, and the extending direction is not necessarily the maximum curvature line of the curved portion B. does not have to match The maximum curvature line is a curve obtained by continuously tracing the direction in which the curvature of the cross section (normal curvature) is maximum on the curved surface. In addition, the configuration of the reinforcing fibers F of the layers L1 and L2 of the FRP composite material 2 is the same as the configuration of the reinforcing fibers F of the layers L1 and L2 in the FRP base material 1 after bending deformation described with reference to FIGS. 3 to 5. Therefore, the description is omitted.

In the FRP composite material 2, both the outermost layer Lo and the innermost layer Li of the curved portion B are composed of a layer L2 having corrugated fibers, and the core layer between the outermost layer Lo and the innermost layer Li is , a layer L1 having straight fibers. Further, a layer Loa adjacent to the outermost layer Lo in the radial direction r of curvature, and a layer Lia adjacent to the innermost layer Li in the radial direction r of curvature are formed of the layer L1. The extending direction (Y direction) of the linear fibers of the layer L1, which is the layers Loa and Lia, is orthogonal to the extending direction (X direction) of the wavy fibers of the layer L2, which is the outermost layer Lo and the innermost layer Li. doing. Therefore, the FRP composite material 2 can obtain the above effects (1) to (3) at the curved portion B.

<Modification>
In the FRP composite material 2 according to the present embodiment, both the outermost layer Lo and the innermost layer Li of the curved portion B are composed of the layer L2, but at least one of the outermost layer Lo and the innermost layer Li It suffices if it is composed of the layer L2. Also in this case, the effect of (1) can be obtained in the layer composed of the layer L2.

Also, in the FRP composite material 2, a plurality of layers L1 are laminated, but one or more layers L1 suffice. Furthermore, in the FRP composite material 2, each of the outermost layer Lo and the innermost layer Li is composed of one layer L2, but each of the outermost layer Lo and the innermost layer Li may be composed of a plurality of layers L2. In any of these cases, since the layer L2 constituting the outermost layer Lo and the innermost layer Li and the layer L1 constituting the layers Loa and Lia are adjacent to each other, the above effect (2) can be obtained. . In addition, in the FRP composite material 2, the core layers other than the outermost layer Lo and the innermost layer Li are composed of a plurality of layers L1, but a layer L2 may be interposed between these layers L1. . The same effect as the above (2) can be obtained between the intervening layer L2 and the adjacent layer L1.

When the outermost layer Lo of the FRP composite material 2 is composed of a plurality of layers L2, for example, in order to obtain isotropic strength characteristics in the outermost layer Lo, the extending direction of the corrugated fibers of each layer L2 is the curvature radius direction. Lamination may be performed so as to form 90°/−45°/45°/0° from the outer side of r. The same applies when the innermost layer Li is composed of a plurality of layers L2. In these cases, the extending direction of the wavy fibers (X direction) and the extending direction of the straight fibers ( Y direction) are orthogonal to each other, the above effect (3) can be obtained.

<FRP preform>
Next, an FRP preform 3 according to another embodiment will be described. As shown in FIG. 3, the FRP preform 3 is a plate-like member having a curved portion B curved in the thickness direction at least partially. In addition, the shape of the curved portion B is not limited to the one shown in the figure, and may be one in which the radius of curvature changes depending on the position, or may be a three-dimensional curved surface shape. Further, the shape of the portion of the FRP preform 3 other than the curved portion B is not particularly limited, and may be flat.

The FRP preform 3 is a preform obtained from the FRP base material 1 described above, and the FRP composite material 2, which is a molded product, can be obtained by performing main molding of the FRP preform 3 by press molding or the like. . Therefore, the curved portion B is composed of two layers L2 and a plurality of layers L1 laminated therebetween. The curved portion B of the FRP preform 3, the layers L1 and L2, the configurations of each modified example, and the effects obtained from these configurations are the curved portion B, the layers L1 and L2 of the FRP composite material 2, and each modified example. Since the configuration and effects are the same as those of , description thereof is omitted.

The above embodiments and modifications are merely examples described to facilitate understanding of the invention. The technical scope of the invention is not limited to the specific technical matters disclosed in the above embodiments and modifications, but also includes various modifications, alterations, alternative techniques, etc. that can be easily derived therefrom.

1 FRP base material 2 FRP composite material 3 FRP preform B Curved portion L1 First layer L2 Second layer F Reinforcing fiber R Resin A Amplitude r Curvature radial direction Li Innermost layer Lo Outermost layer Lia Innermost layer and curvature radial direction Adjacent layer Loa Layer adjacent to the outermost layer in the direction of curvature radius Z Lamination direction Ls Outermost layer (outermost layer in the lamination direction)
Lsa Layer adjacent to the outermost layer in the stacking direction

Claims (6)

A plate-shaped FRP composite material,
Having a curved portion curved in the thickness direction at least in part,
The curved portion is
one or more first layers in which reinforcing fibers are aligned in a straight line;
one or more second layers in which reinforcing fibers are aligned and meandering with an amplitude in a direction orthogonal to the thickness direction;
is composed of
An FRP composite material characterized in that at least one of an outermost layer positioned on the outermost side and an innermost layer positioned on the innermost side in a curvature radius direction of the curved portion is composed of the second layer. The innermost layer is composed of the second layer,
2. The FRP composite material according to claim 1, wherein the innermost layer and the layer adjacent to the outer side in the curvature radial direction are composed of the first layer. A plate-like FRP preform,
Having a curved portion curved in the thickness direction at least in part,
The curved portion is
one or more first layers in which reinforcing fibers are aligned in a straight line;
one or more second layers in which reinforcing fibers are aligned and meandering with an amplitude in a direction orthogonal to the thickness direction;
is composed of
An FRP preform, wherein at least one of an outermost layer positioned on the outermost side and an innermost layer positioned on the innermost side in a curvature radius direction of the curved portion is composed of the second layer. The innermost layer is composed of the second layer,
4. The FRP preform according to claim 3, wherein the innermost layer and the layer adjacent to the outer side in the curvature radial direction are composed of the first layer. An FRP base material in which a plurality of layers each composed of aligned reinforcing fibers and a resin impregnated in the reinforcing fibers are laminated,
Having a curved portion curved in the thickness direction at least in part,
The curved portion is
one or more first layers in which the reinforcing fibers are aligned in a straight line;
one or more second layers in which the reinforcing fibers meander with an amplitude in a direction perpendicular to the thickness direction;
is composed of
An FRP base material, wherein at least one of an outermost layer positioned on the outermost side and an innermost layer positioned on the innermost side in a curvature radius direction of the curved portion is composed of the second layer. The innermost layer is composed of the second layer ,
6. The FRP base material according to claim 5, wherein the innermost layer and the layer adjacent to the outer side in the curvature radial direction are composed of the first layer.

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